Improving Estimates of Neighborhood Change with Constant Tract Boundaries.

Social scientists routinely rely on methods of interpolation to adjust available data to their research needs. Spatial data from different sources often are based on different geographies that need to be reconciled, and some boundaries (e.g., administrative or political boundaries) change frequently. This study calls attention to the potential for substantial error in efforts to harmonize data to constant boundaries using standard approaches to areal and population interpolation. The case in point is census tract boundaries in the United States, which are redefined before every decennial census. Research on neighborhood effects and neighborhood change rely heavily on estimates of local area characteristics for a consistent area of time, for which they now routinely use estimates based on interpolation offered by sources such as the Neighborhood Change Data Base (NCDB) and Longitudinal Tract Data Base (LTDB). We identify a fundamental problem with how these estimates are created, and we reveal an alarming level of error in estimates of population characteristics in 2000 within 2010 boundaries. We do this by comparing estimates from one of these sources (the LTDB) to true values calculated by re-aggregating original 2000 census microdata to 2010 tract areas. We then demonstrate an alternative approach that allows the re-aggregated values to be publicly disclosed, using "differential privacy" (DP) methods to inject random noise that meets Census Bureau standards for protecting confidentiality of the raw data. We show that the DP estimates are considerably more accurate than the LTDB estimates based on interpolation, and we examine conditions under which interpolation is more susceptible to error. This study reveals cause for greater caution in the use of interpolated estimates from any source. Until and unless DP estimates can be publicly disclosed for a wide range of variables and years, research on neighborhood change should routinely examine data for signs of estimation error that may be substantial in a large share of tracts that experienced complex boundary changes.

The Nonlinear Effect of Informal Social Control on Repeat Intimate Partner Violence Victimization.

Prior research has examined the effects of neighborhood context on intimate partner violence (IPV) with mixed results. While most studies find that neighborhood disadvantage is positively associated with risk of IPV, the effects are less consistent for characteristics such as social ties and informal social control. One possible explanation for these mixed findings draws from theoretical and empirical literature arguing that a high level of collective efficacy can aid in the control of criminal behavior, but it can also deter residents from acting against crime committed by neighbors. This suggests the possibility of a nonlinear effect of collective efficacy where the risk of IPV may be high in areas with very low levels of collective efficacy because of the inability of neighborhoods to collectively control residents, but it may also be high in areas with very high levels of collective efficacy where residents are less willing to report on the criminal behavior of fellow residents. We test this possibility using survey data for female victims of IPV in Chicago merged with neighborhood characteristics. Findings suggest that the risk of repeat victimization is highest in areas with either very high or very low levels of informal social control.

Segregation of minorities in the metropolis: two decades of change.

Data from Census 2000 show that black-white segregation declined modestly at the national level after 1980, while Hispanic and Asian segregation rose in most metropolitan areas. Changes that may have produced greater changes for blacks proved to have insignificant effects: there was no net shift of the black population toward less-segregated areas, segregation at the metropolitan level did not decline more in areas where the incomes of blacks came closer to the incomes of whites over time, and the emergence of more multiethnic metropolises had no impact. As in the past, declines were centered in the South and West and in areas with smaller black populations. Increases in Hispanic and Asian segregation in individual metropolitan areas were counterbalanced by a net movement of these two groups toward areas of lower segregation. These increases were associated especially with the more rapid growth in the Hispanic and Asian populations. Hispanic segregation increased more in regions where group members had declining incomes relative to the incomes of whites and included a growing share of immigrants.